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Introduction: The new reassortant of the swine flu virus A(H1N1)pdm09, which emerged in 2009, overcame the species barrier and caused the 2009-2010 pandemic. One of the key points required for the influenza virus to overcome the species barrier and adapt it to humans is its specific binding to the receptors on the epithelium of the human respiratory tract., Purpose: Studying the dynamics of changes in receptor specificity (RS) of the HA1 subunit of the hemagglutinin of the influenza A(H1N1)pdm09 virus strains isolated during the period 2009-2016 on the territory of the Russian Federation, and an analysis of the possible impact of these changes on the incidence rates of the population of the Russian Federation of pandemic influenza in certain epidemic seasons., Material and Methods: Standard methods of collecting clinical materials, isolation of influenza viruses, their typing and genome sequencing were used. For the study of RS of influenza A virus (H1N1)pdm09, the method of solid phase sialosidenzyme analysis was used., Results: It is shown that the change in the parameter W 3/6 , which characterizes the degree of a2-3 receptor specificity (a2-3-RS) of the influenza virus A(H1N1) pdm09 over a2-6-RS, coincides with the change in the incidence rates of the Russian Federation's pandemic flu in separate epidemic seasons. There is a tendency to increase the affinity of the virus A(H1N1)pdm09 to α2-3 analogs of the sialyl-glycan receptors of the human respiratory tract epithelium - α2-3-sialoglycopolymers (α2-3-SGP), and falls to α2-6-SGP, with the virus showing the greatest affinity for sulfated sialoglycopolymers., Discussion: Screening for RS strains of influenza A (H1N1)pdm09 virus isolated on the territory of the Russian Federation in 2009-2016 revealed a decrease in the affinity of viruses for a2-6-sialosides, especially for 6'SL-SGP, which is probably due to the presence of amino acid substitutions in the 222 and 223 positions of RBS HA1 viruses. Previous studies have shown that the presence of such substitutions correlates with an increase in the virulence of the influenza A virus (H1N1)pdm09 [16, 23]. Probably, the pandemic virus has evolved towards the selection of more virulent pneumotropic variants., Conclusion: Monitoring of the receptor specificity of a pandemic influenza virus makes it possible to identify strains with altered RS to the epithelium of the human respiratory tract and an increased ability to transfer from person to person. Change in the period 2009-2016 the W 3/6 parameter characterizing the degree of α2-3-RS excess of the influenza A(H1N1)pdm09 virus over α2-6-RS, coincides with the change in the incidence rates of the pandemic influenza population of the Russian Federation in certain epidemic seasons., Competing Interests: The authors declare no conflict of interest.

The paper gives the results of monitoring the circulation of influenza viruses in the 2010-2011 season, that covers the second year of circulation of pandemic A(H1N1)v virus strains, and their interaction with seasonal A (H3N2) and B strains. Unlike the previous season, the beginning of an increase in morbidity was recorded in January 2011; its peak in the most of contiguous areas was noted at 5-7 weeks of 2011, with its further decline to threshold levels at week 11 of 2011. Preschool and school children were most involved in the epidemic process. Three influenza virus strains (A(H1N1)v, A(H3N2), and B) were found to circulate. Differences were found in the level of participation of the isolated strains in individual areas of the Russian Federation. Detailed typing of the isolated strains determined the compliance of the vast majority of them with vaccine viruses. The pandemic influenza A(H1N1)v virus strains retained their susceptibility to oseltamivir and were resistant to rimantadine. The participation of non-influenza acute respiratory viral infection pathogens was estimated as follows: 11.9% for parainfluenza viruses, 5.9% for adenoviruses, and 3.5% for PC viruses, and 0.7% for pneumonia Mycoplasma, which was comparable with the previous epidemic seasons.

Aim: To assess efficacy and safety of ingavirin in the treatment of the flu caused by pandemic virus of flu A (H1N1) sw1 in hospitalized patients compared with oseltamivir., Material and Methods: A population-based comparative multicenter trial included 194 patients with verified diagnosis of the flu aged 18-60 years with marked clinical symptoms, body temperature over 38 degrees C and duration of the disease 48 hours maximum. The patients were randomized into 2 groups: group 1 (n=152) received ingavirin (90 mg once a day), group 2 received oseltamivir (n=42) in a dose 150 mg twice a day. Duration of the course was 5 days., Results: Ingavirin and oseltamivir normalized body temperature within treatment hours 24-36 if therapy was initiated in the first disease hours 27.0 +/- 10.0 and 31.9 +/- 10.4. Mean duration of the fever for ingavirin was 35.1 +/- 14.5 hours, for oseltamivir--26.3 +/- 13.0 hours (p < 0.817). The antiviral medicines significantly reduced duration of intoxication (head ache, weakness), catarrhal symptoms (cough, tracheitis, rhinitis), rate of complication vs. patients untreated with antivirus drugs (n=30)., Conclusion: The results of the treatment show safety and efficacy of ingavirin in uncomplicated flu caused by pandemic virus of flu A (H1N1) sw1 in inpatients. Early etiotropic therapy is a basic treatment policy able to reduce the number of severe complications and lethality.